1. Technical Field
This invention generally relates to windows having muntin bars that simulate the appearance of traditional divided lite windows having individual panes of glass set in wooden muntin bars. More particularly, the present invention relates to a method of fabricating muntin bars on automated machinery for use in simulated divided lite windows. Specifically, the present invention relates to a method of automatically sizing, cutting, and joining foam strips to the top and bottom edges of traditional thin metal inner muntin grid elements for use in insulating windows having outer muntin bars positioned in coincidental alignment with the inner muntin bars. The invention also relates to the structure of the muntin bars.
2. Background Information
Traditional windows have individual panes of glass separated by wooden muntins. While these windows are attractive and have functioned for many years, they are relatively expensive to fabricate. The expense is particularly high when a consumer desires an insulating window having spaced panes of glass sealed together by a perimeter spacer. A single window having twelve panes of glass requires twelve spacers, twenty-four panes of glass, and a precisely formed muntin grid. In addition to the cost of materials, the assembly process is also relatively expensive. Thus, although consumers desire the aesthetic properties of traditional divided lite windows, most are unwilling to pay for a true divided lite window.
Modern, energy efficient insulating windows include at least two panes of glass separated by a spacer to form a sealed cavity that provides insulating properties. These insulating windows are most efficiently manufactured with two large panes of glass separated by a single spacer disposed at the perimeter of the panes. Various solutions have been implemented to provide the divided lite appearance in insulating windows. One solution to the problem has been to place a muntin bar grid between the panes of glass. Another solution has been to place the muntin bar grid on the outer surface of one, or both, panes of glass. Although these solutions provide options for consumers, each has visual drawbacks when compared with traditional muntin bars.
Placing muntin bar grids between the panes of glass is one of the most common solutions to the divided lite problem. In fact, so many internal muntin grids are fabricated that automated muntin bar manufacturing equipment has been created and is used in the art. This equipment works in cooperation with the automated window manufacturing equipment. In this equipment, the user inputs the desired size of window and the computer automatically selects the ideal number of grid intersections to form an aesthetically pleasing muntin bar grid. In other embodiments, the user may override the automatic selection and manually select the number of muntin bar intersections in the grid. The computer then controls automated fabricating equipment that roll forms flat metal stock into the hollow, substantially rectangular muntin bars used to form the muntin bar grid. The muntin bars are dadoed or notched at their intersections half-way through their thickness to provide the overlapping joint required to form the grid. These notched areas are also automatically formed. The muntin bars are then cut to length and an assembler manually assembles the bars into a grid that is mounted to the spacer that spaces the inner and outer panes of glass. The muntin bar grid is attached to the spacer with specially designed clips that fit into holes punched into the spacer during the manufacture of the spacer. These systems allow muntin bar grids to be quickly and easily manufactured for a relatively low price after the user invests in the automated equipment. The muntin bar grids are painted and deburred to have a pleasing appearance either before or after the grid is assembled.
One product developed by Edgetech I.G. of Cambridge, Ohio, in response to the insulating window muntin bar problem includes the use of a pair of material strips positioned on the upper and lower edges of metal muntin bars inside an insulating window assembly. Outer muntin bars are then provided in coincidental alignment with the inner muntin bars to achieve a simulated divided lite appearance. The material strips visually join the aligned outer muntin bars to create the appearance that the muntin bar grid extends entirely through the insulated window assembly. This product also hides the metal muntin bars. The metal muntin bars thus do not have to be painted and may be fabricated from a lower quality material than exposed, painted inner metal muntin bars. Although this product achieved acceptance by the consumer because of its visual appearance, the insulating window manufacturers objected to the relatively large amount of labor required to size, cut, and install the material strips. It is thus desired in the art to provide a method for sizing, cutting, and installing the material strips to muntin bars that are fabricated with automated machinery.
Another problem encountered with this product occurs when the material strips are stretched during installation or applied to the outside of a curved muntin. It has been found that the strips relax overtime and delaminate causing the window to have an unattractive appearance. It is desired in the art to provide a solution to this delamination problem.
In view of the foregoing, it is an objective of the present invention to provide a method for fabricating muntin bars for simulated divided lite windows.
Another objective of the present invention is to provide a method for creating muntin bars for simulated divided lite windows wherein material strips are automatically sized, cut, and applied to the muntin grid elements that are then assembled into a muntin bar grid.
Another objective of the present invention is to provide a method for creating muntin bars for simulated divided lite windows wherein the muntin grid elements are roll formed from metal stock and automatically cut to length with the material strips being fabricated based on the data used to roll form the muntin grid elements.
Another objective of the present invention is to provide a method for fabricating a muntin bar grid wherein the person fabricating the grid only needs to provide the window size and the number of desired panes as well as to assemble the muntin bar grid after the individual muntin grid pieces are fabricated.
Another objective of the present invention is to provide a method for fabricating a muntin bar grid wherein muntin grid elements are provided and measured, with the measurements being used to fabricate the material strips that are then applied to the grid elements.
Another objective of the present invention is to provide a method, as above, wherein opposed strips of material are simultaneously cut to length and applied to the grid element.
Another objective of the present invention is to provide a method, as above, wherein the strips of material are formed with flaps that cover a portion of the muntin clips when the insulating glazing unit is assembled.
Another objective of the present invention is to provide a method wherein the strips of material include a non-extensible material to prevent the strips from stretching during installation.
Another objective of the present invention is to provide foam strips for use with muntin bars wherein the foam strips have a non-extensible material connected to the foam strip to prevent the foam strip from stretching when it is used around curves.
Another objective of the present invention is to provide strips for use with muntin bars wherein a mechanical connection is formed between the strips and bars to help prevent delamination.
A further objective of the present invention is to provide a method of fabricating muntin bars for simulated divided lite windows that achieves the stated objectives in a simple, effective, and inexpensive manner that solves the problems, and that satisfies the needs existing in the art.
These and other objectives and advantages of the present invention are obtained by a method for fabricating muntin grid pieces wherein each muntin grid piece includes a muntin grid element and a pair of material strips connected to opposed edges of the muntin grid element; the muntin grid pieces being capable of being assembled into a muntin bar grid for a window; the method including the steps of: (a) providing a muntin grid element having a length; (b) providing material strip stock having a pair of connected material strip lengths; (c) simultaneously cutting the material strip stock to a length related to the length of the muntin grid element; (d) separating the pair of connected material strip lengths to provide a pair of material strips; and (e) connecting the pair of material strips to the muntin grid element to form a muntin grid piece.
Other objectives and advantages of the invention are achieved by a method for fabricating a muntin bar grid for a window including the steps of: (a) providing at least two muntin grid elements; (b) providing at least two material strips; (c) connecting at least one material strip to each of the muntin bars to form muntin pieces; and (d) assembling the muntin pieces together to form a muntin bar grid after the material strips are connected to the muntin grid elements.
Other objectives and advantages of the invention are achieved by a muntin piece assembly for a muntin grid; the muntin piece including: at least one muntin grid element having a width, a thickness, and a longitudinal length; the muntin grid element having first and second ends separated by the longitudinal length of the muntin grid element; the muntin grid element further having first and second edges separated by the width of the muntin grid element; a first clip connected to the first end of the muntin grid element; and at least a first material strip connected to the first edge of the muntin grid element; the first material strip having a first flap that covers at least a portion of the first clip.
Other objectives and advantages of the invention are achieved by a material strip for a muntin piece in a simulated divided lite muntin bar grid, the material strip including: a body having a width, a thickness, and a longitudinal length; and a non-extensible member connected to the body and extending in the longitudinal direction.
Other objectives and advantages of the invention are achieved by a muntin grid piece for a muntin bar assembly; the muntin grid piece including: at least one muntin grid element having a width, a thickness, and a longitudinal length; the muntin grid element having first and second ends separated by the longitudinal length of the muntin grid element; the muntin grid element further having first and second edges separated by the width of the grid element; at least a first material strip connected to the first edge of the muntin grid element; and the first material strip being mechanically connected to the muntin grid element.